Big Picture News, Informed Analysis

This blog is written by Canadian journalist Donna Laframboise. Posts appear Monday, Wednesday & Friday.

Defining High Blood Pressure

SPOTLIGHT: Blood pressure guidelines should be raising eyebrows.

BIG PICTURE: A blood pressure reading measures the strength at which your blood surges against the walls of your arteries when your heart beats (the first number), followed by the strength of the pressure when your heart is at rest (the second number).

The first number is key. Until the 1970s, the rule of thumb was that you were healthy if it didn’t exceed your age plus 100. A 60-year-old with a blood pressure reading of 150 was in the clear.

In recent decades, the definition of high blood pressure has changed dramatically. Now, to be considered ‘normal,’ your reading has to be below 120. A 2017 policy statement from the American Hearth Association says that everyone with a reading of 120 and over requires medical intervention. This includes monitoring every 3-6 months, drugs for those with a reading of 140 or higher, and drugs for some people in the 130-139 range.

Medical critics such as Malcolm Kendrick think the definition of ‘normal’ blood pressure is becoming too stringent, and that insufficient attention is being paid to the downside of medications now prescribed to an ever-larger percentage of the population.

While these pills work well for some people, side effects adversely affect many others. Impotence and lethargy are not trivial matters. Nor are life-threatening allergic reactions. Drugs also cost money – they are an expense borne by patients, insurance companies, and governments.

Curiously, the 114-page document in which the latest guidelines were published fails to address a powerful critique published in the European Heart Journal back in 2000. A statistician and two cardiologists (Sidney Port, Alan Garfinkel, and Noel Boyle), argue that lower numbers don’t automatically lead to better outcomes. They say that if we made a list of the blood pressure readings of 100 people of the same sex and approximate age, starting with the highest readings at the top and descending to the lowest readings at the bottom, everyone in the bottom 70 is at equally low risk.

It’s the 20 people at the top who are in trouble, they say. A medical system interested in extending lives would focus its attention on those people (and, to a lesser degree, on individuals who are 71-80 on the list.)

If Port and his colleagues are correct, doctors are wasting enormous amounts of time and money trying to lower the blood pressure of already low-risk patients. Even if this therapy is successful there may be little to be gained from all that effort.

TOP TAKEAWAY:  Doctors are, first and foremost, supposed to do no harm. Millions of unnecessary prescriptions increase the risk of adverse drug interactions – and expose patients to unnecessary side effects. That harm is real.

LINKS:

Doctoring Data: How to sort out medical advice from medical nonsense
Malcolm Kendrick
  • Port, Garfinkel & Boyle’s 2000 statistical analysis and critique of mainstream thinking.
  • The November 2017 blood pressure guidelines are found on p. 47 of this 114-page document. In the blink of an eye, an additional 31 million Americans were suddenly classified as having high blood pressure when that document was released.
  • This news story describes how, after her doctor doubled her dose of a new blood pressure medication, an otherwise healthy 71-year-old suffered “an allergic reaction that could have killed her.”
  • my related commentary, Bogus blood pressure readings

 

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This entry was posted on March 12, 2018 by in quotations and tagged , , .
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